This invention relates to the art of cartridges for dispensing ink, and more particularly, to cartridges for dispensing ink that use a reduced-pressure area in the cartridge to more efficiently use the capacity of the cartridge, to increase the shelf life and quality of the ink dispensed, and to minimize leakage from the cartridge by minimizing the volume and pressure of extraneous fluids (e.g., air) retained in the cartridge and in the ink therein.
Cartridges for dispensing ink have been provided heretofore, and generally are comprised of a housing having a cavity therein for storing a quantity of ink, and a dispensing port extending through the housing from the cavity through which ink may flow. Such a cartridge is operatively associated with an output recordation device, such as a printer. Typically, the printer has a printhead, and the dispensing port is in fluid communication with the printhead so that ink can be transferred from the cavity in the cartridge to the output medium, such as paper.
A housing generally has a top wall, such as a cover, that extends across the top of the housing to fully enclose the cavity. The cover is secured to the housing forming a fluid-tight seal along a seam between the housing and the cover. One or more ports, in addition to the dispensing port, may extend through the housing to permit the ingress and egress of ink or air. Once the cover has been secured to the housing and the cartridge has become a generally closed container, the cartridge is filled with ink. At various stages throughout this filling process, the dispensing port and other ports will be sealed to prevent leakage and evaporation of the ink.
In ink cartridges of the foregoing character, air may be retained in the cartridge during the filling process. The trapped air can mix into the ink during the filling process or after the filling process. This can reduce the storage life of the ink cartridge, result in interruption of ink flow from the cartridge and lead to a reduction in the quality of output from a printer using such a cartridge. Air trapped in the cartridge may expand in response to temperature or pressure changes and thereby undesirably force some of the stored ink from the cartridge. To minimize such print voids or other problems, ink cartridges are often filled in a reduced-pressure environment. A variety of difficulties are encountered when employing such a filling procedure. The filling operation often requires expensive equipment to perform the filling operation under these conditions. Sealing the port in a conventional manner, such as by plugging or covering the ports, does not overcome the problem of air entrapped in the cartridge either prior to or during the filling process. Furthermore, once the cartridge has been sealed in a conventional manner, there is no way to remove entrapped air from the cartridge. As such, it will be appreciated that filling cartridges in this manner can be difficult and inefficient, often requiring expensive equipment to effectively perform such filling operations, and may still lead to a reduction in the quality of ink cartridges.
In accordance with the present invention, an ink cartridge is provided that avoids or minimizes the problems and difficulties encountered with ink cartridges of the foregoing nature, while promoting the desired simplicity of structure, economy of manufacture, ease of assembly, and maintaining the quality of ink stored and dispensed in association with such ink cartridges.
More particularly, in this respect, ink cartridges according to the invention include a housing having a cavity therein for the storage of a quantity of ink. A dispensing port extends through the housing from the cavity such that ink may be dispensed through the port. The housing has a top wall, such as a cover, extending there across and enclosing the cavity. In the present embodiment, the top wall is in the form of a cover and is secured to the housing by welding, bonding or adhesive, for example, forming a fluid-tight seal with the housing. In addition to the dispensing port, the housing may have one or more additional ports extending therethrough placing the cavity in fluid communication with the ambient atmosphere. One of the additional ports, the vacuum port, is fitted with a check valve that permits the flow of fluid through the port in substantially one direction.
The check valve is supported on the cartridge adjacent the vacuum port, and permits fluid to flow from the cavity inside the cartridge out through the port without permitting substantial flow of fluid in the reverse direction, that is, flow of fluid into the cavity from the ambient atmosphere.
An arrangement of the vacuum port and check valve according to the subject invention includes an elastomeric check valve having a body portion and a valve portion, and a vacuum port having a retaining portion and a fluid-passage portion. The body portion of the check valve is housed in the retaining portion of the vacuum port such that the fluid-passage portion remains substantially unobstructed. The valve portion of the check valve extends from the body portion along the exterior of the housing beyond the fluid-passage portion of the vacuum port and engages an external surface of the housing forming a fluid-tight seal between the valve portion and the external surface.
Accordingly, the present invention advantageously provides a cartridge for dispensing ink in which the ink is stored under a reduced pressure relative to the ambient atmosphere, and the cartridge includes a check valve that facilitates removal of air trapped in the cartridge after the filling process.
Other advantages of the invention reside in improved print quality and operation, as well as extended shelf life of the ink cartridge.
Furthermore, an ink cartridge of the foregoing character is comprised of a minimum number of parts and is structurally simple, thereby promoting and maintaining the economical production of the ink cartridge.
Still other benefits and advantages will become apparent to those skilled in the art upon reading and understanding the following detailed description.